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Q1. A single plate clutch with both sides effective has an outside diameter of 380 mm and an inside diameter of 140 mm. The clutch is designed to transmit 12 kW at 600 rev/min. The axial thrust on the clutch faces is provided by six identical springs, each with a stiffness of 8 kN/m. The coefficient of friction at the clutch surfaces is 0.6. Calculate EACH of the following:

(a) The required compression of each spring to deliver the designed power when the clutch is new;

(b) The power transmitted when a total of 2 mm of plate wear occurs and the clutch is worn.

Note: For constant pressure, T =   (2μnW(R_o³-R_i³)/3(R_o²-R_i² )

For constant wear, T = (μNw(r_o+ r_i))/2

n = number of pairs of contact surfaces.

Q1. A compound bar consists of a round copper bar of 28mm diameter tightly encased in a steel tube 40mm diameter and of the same length. A tensile load of 100kN is applied. Calculate EACH of the following:

(a) The stress in the copper bar;

(b) The stress in the steel.

Note: For steel, Modulus of Elasticity = 210 GN/m²

For copper, Modulus of Elasticity = 90 GN/m²

Q1. A symmetrical I-shaped beam is shown in Fig. The beam is simply supported at both ends and carries a uniformly distributed load of 30kN per meter length and a single concentrated load of 6kN at mid-span. Calculate the maximum permissible length of the beam if the bending stress in the beam is not to exceed 140 MN/m².